JP2531247B2 - Electron density conversion digitizer input mechanism - Google Patents

Description

The present invention relates to an electron density conversion type digitizer input mechanism, and more particularly to an electron density conversion type digitizer input mechanism for CT images in a radiation treatment planning apparatus.

[Conventional technology]

Conventionally, this kind of electron density conversion mechanism directly inputs a CT image, which has been a digital value, to a radiation treatment planning device by directly inputting it with a magnetic tape, a flexible disk medium or online, so that the digital value is directly converted into an electron density. Or the indirect method of manually tracing the CT image that has become a film and manually inputting the electron density value for each organ contour, or by electrically tracing the film to determine the film density. It is based on a quasi-indirect means that performs conversion based on a predetermined conversion formula.

[Problems to be Solved by the Invention]

The conventional electron density conversion mechanism described above calculates basic data for calculating the radiation distribution in the body by converting the CT image into electron density, but with the digital CT image direct conversion mechanism, the CT for each CT device is calculated. Due to the problem that the image formats are different, there is a drawback that it is necessary to have a plurality of types of conversion programs. Further, in the manual indirect input means, the electronic density conversion is not performed and the direct designation is performed manually, which has a drawback in accuracy. Further, in the method of electrically tracing the film, it is necessary to separately install a tracing device, which has drawbacks in setting space, installation cost, and conversion accuracy.

[Means for solving the problem]

The electron density conversion type digitizer input mechanism of the present invention is a backlight type digitizer input mechanism, a tablet with a pen type optical sensor, an A / D converter for AD converting the optical sensor output of the tablet, a film density / electronic Density conversion designating mechanism, an instantaneous value display mechanism for momentarily displaying the instantaneous value of the electron density value determined by the designation of the film density electron density conversion designating mechanism from the output signal of the A / D converter, and the instantaneous value Data storage mechanism that stores the data of a certain period, an average value display mechanism that displays the average value of the data from the storage of the data to an arbitrary elapsed time, and a standard deviation that displays the standard deviation value of the data A value display mechanism and a most-occurring-value display mechanism for displaying the most-occurring-value,
A plurality of in-contour electron density storage mechanisms are used as the in-contour electron density of the predetermined trace range as the in-contour electron density, and an electron density table calculation mechanism that finally calculates the entire electron density table for one original image. Composed.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

 FIG. 1 is a block diagram of an embodiment of the present invention.

The pen 1 is supplied to the photosensor 2 to form a pen-shaped photosensor-equipped tablet 1A. The pen 1 with a light sensor arbitrarily traces within a certain contour on the CT screen film photograph placed on the backlight digitizer input mechanism. The signal output from the tablet with pen-shaped optical sensor 1A is A /
The D converter 3 converts the optical signal into a digital signal. In the tablet 1A with a pen-shaped optical sensor,
A CCD element is incorporated and the intensity of the output signal changes according to the light intensity. The film image of the CT image is a film in which the CT value is converted into a film according to the density difference between black and white.Therefore, by reading the density difference of the film as a light intensity difference with the CCD element, it is compared with the original CT value. Can be made.

The keyboard 4 accesses the film density electron density conversion designating mechanism 5 in order to define a conversion rule when converting the level of the output value of the A / D converter 2 into an electron density proportional to the radiation absorption density. When the pen 1 with a photosensor traces a certain contour on a CT image film photograph, the electron density at that point is displayed on the instantaneous value display mechanism 6 as an instantaneous value.

When the pen 1 traces an arbitrary position, the size of the data storage mechanism 7, which stores the instantaneous value in the data storage mechanism 7 at any time, can be changed by the mechanism of the system, but the range of tracing is 50 to 100 points. Having as a limit is done. As long as this limit is not exceeded, the input signal is stored in the data storage mechanism 9. The output of the A / D converter 3 is converted into electron density by the film density electron density conversion mechanism 5, and all the data handled by the instantaneous value display mechanism 6 and the data storage mechanism 7 are data after conversion to electron density. When an arbitrary trace within a certain area is continued and a typical trace within an area is completed, the average value display mechanism 8 until an arbitrary elapsed time displays the average value and the standard deviation value display mechanism 9 Indicates the standard deviation value, and the most-appearing value display mechanism 10
Displays the maximum value in the traced range. The CT image film to be traced is preliminarily divided into a plurality of contours showing the affected part such as an organ that requires radiation irradiation, and the electron density irradiating the inside of the contour of the affected part is determined as one representative value. In this case, the average value indicated by the average value display mechanism 8 is taken, or the average value is arbitrarily corrected from the keyboard with reference to the standard deviation value indicated by the standard deviation display mechanism 9, or the highest occurrence value indicated by the highest occurrence value display mechanism 10 is displayed. The average value is arbitrarily corrected with reference to, and the representative value is determined. The electron density is determined for each of a plurality of contours, and the CT image film photograph stored in the intra-contour electron density storage mechanism 11 has the electron density determined on a predetermined matrix and defined in the electron density table 12. In general, the contour boundary and the electron density matrix defined in a grid pattern do not match, so when allocating the electron density for each lattice of the electron density matrix, some lattices are divided by the contour boundary, but in that case The electron density is calculated in accordance with the divided area ratio.

As shown in FIG. 2, the CT image film photograph 20 has the contour parts 21 to 25 of the internal organs traced in advance. Next, the optical sensor pen 1 traces the body surface vicinity 26 and the body surface vicinity 26. The electron density is determined by using as one representative value of one body organ (for example, epidermis). Similarly, the contour portion 23, the contour portion
24 and the contour portion 25 are traced in a zigzag manner by the pen 1 with an optical sensor to obtain electron density.

FIG. 3 is an electron density figure when the electron density in each contour portion is determined and then the electron density is assigned to lattice points on a predetermined electron density matrix. Although the magnitude of the electron density is expressed by the difference in density between black and white, the electron density is defined on the calculation matrix within the range handled in the calculation.

〔The invention's effect〕

As described above, according to the present invention, by tracing the inside of an arbitrary shape of a CT image film photograph by using a tablet with a pen-shaped optical sensor, the average electron density within the arbitrary shape is known, and the standard deviation value and the maximum number of appearances occur. There is an effect that the means for determining the optimum electron density by referring to the value is provided, and the electron density matrix can be obtained for the image on the film by a simple method.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a trace situation diagram, and FIG. 3 is an electron density matrix diagram. 1 ... Pen, 2 ... Optical sensor, 3 ... A / D converter, 4
...... Keyboard, 5 …… Film density electron density conversion designation mechanism, 6 …… Instantaneous value display mechanism, 7 …… Data storage mechanism,
8: Average value display mechanism, 9: Standard deviation value designation mechanism, 10
...... Maximum appearance value display mechanism, 11 …… Electron density storage mechanism in contour, 12 …… Electron density table, 20 …… Body contour, 21-25…
… Outline, 26 …… Near the body surface.

Claims (1)

(57) [Claims] 1. A backlight type digitizer input mechanism, a tablet with a pen type optical sensor, an A / D converter for AD converting the optical sensor output of the tablet, a film density / electron density conversion designating mechanism, and From the output signal of the A / D converter, the film density electron density conversion designating mechanism determines the momentary value of the electron density value determined by the designation of the momentary value display mechanism, and stores the data of the momentary value for a certain period of time. A data storage mechanism, an average value display mechanism for displaying the average value of the data from the storage of the data to an arbitrary elapsed time, a standard deviation value display mechanism for displaying the standard deviation value of the data, and the maximum occurrence value. A maximum appearance value display mechanism for displaying, a plurality of in-contour electron density storage mechanisms for storing the average value as the in-contour electron density of a predetermined trace range, and finally one sheet Electron density conversion type digitizer input mechanism, characterized by comprising an electron density table calculating mechanism for calculating the total electron density table for image.